Various signal light systems have heretofore been devised for the general objective of providing a visual indication of particular operating conditions of an automobile vehicle. These operating conditions are generally actuation of the braking mechanism and an indication as to whether the vehicle is accelerating or decelerating. Automotive vehicles are provided with a factory installed brake light indicating system, but the signal light systems to which this invention is directed is of an auxiliary nature to provide a secondary indication to drivers of vehicles that are following a vehicle provided with a signal light system of this invention. Providing of an auxiliary or secondary brake actuation light enhances vehicular operational safety through the simple provision of a second indicator light for the brakes. More importantly, the ability of the signal light system to provide an indication as to whether the vehicle is accelerating or decelerating and thereby provide an anticipatory signal for a following vehicle is a significant factor in improved safety. An anticipatory system indicating that a vehicle is slowing down or decelerating provides an advantageous preliminary warning signal that the brake system may be actuated and produce a sudden stop.
For an example, a prior art system of this type having the anticipatory signal objectives is disclosed in U.S. Pat. No. 3,676,844. That patent discloses a signalling system utilizing mechanically actuated electrical switches for providing the input signals to the control circuit. A substantial disadvantage of such a system utilizing mechanically actuated switches is that the switches must be manufactured and constructed to withstand severely adverse operating conditions and environments and this materially increases the cost of such systems. Additionally, the mechanically actuated switches require precise positioning and orientation in order to correctly respond to accelerating systems and mechanisms and provide the necessarily indication of acceleration or deceleration. Furthermore, the mechanically actuated switches are not as rapidly functioning as is desired for signalling systems of this type.
A subsequent attempt to improve the operating efficiency and effectiveness of such signal light systems is disclosed in U.S. Pat. No. 3,813,542. That patent discloses a system utilizing an optical-electronic detecting device associated with the accelerator pedal. While the optical-electronic device eliminates, or at least alleviates, some of the disadvantages and defects of mechanically actuated switch devices, it will be readily seen that an optical-electronic device is not capable of providing the desired response in all situations. For example, this system is incapable of detecting deceleration of a vehicle where the operator merely releases the pressure applied by his foot to the accelerator pedal. This ineffectivity results from the fact that the foot remains in the light path and prevents the detection of this deceleration. An optical-electronic device is only effective when the foot is entirely removed from the accelerator pedal and this does not happen in a case with all vehicle drivers. Some drivers maintain the foot on the accelerator pedal while applying the other foot to the brake pedal to provide an unannounced deceleration or braking.